The present invention relates to devices for providing temporary closure of an opening in a solid structure. More particularly, the present invention relates to apparatus for removably covering the opening of a fireplace so that the firebox is securely isolated. The present invention is particularly useful for totally closing the opening of a fireplace so that any fire contained within the firebox can be smothered while further insuring that ashes and sparks will not escape from the firebox while the fireplace is unattended.
Despite the development of central heating systems, there has been continuing interest in including fireplaces within buildings, especially residences. This interest was predominantly ornamental but of recent years the value of the fireplace as a supplementary heat source has drawn increased attention. It has long been recognized that the vagaries of the quality of materials being burned requires some form of protective enclosure in order to reduce the prospect of spark escape from the firebox. Thus portable screens have been employed with these screens being replaced in more recent times by permanently attached sliding screens. In some cases, the screen is partially a transparent panel with openings along the bottom to permit ventilation in order to support the fire. An example of a glass screen with counterbalanced panel mountings for permitting access to the firebox is shown in U.S. Pat. No. 2,939,450 by Rubens.
Of necessity, the ventilating openings either through a mesh screen or the ventilating louvers associated with a transparent screen require some communication to the room environment in which the fireplace is located. Such air communication likewise exposes the possibility that spark escape will occur while the fire is burning as is encountered with burning certain types of wood. While the fire is being attended, this hazard is at least somewhat discounted since sparks can usually be promptly extinguished. However, the fireplace often must be left unattended and thus hazard the possibility of spark escape without notice particularly where the fireplace is subject to strong down drafts from the chimney from the wind. Still further, there are frequent occasions when the combustible materials have not been completely consumed and it is preferred to preserve those materials for later use. Even when the fire has burned out, the possibility exists that ashes and dust from the firebox may be blown out of the fireplace by down drafts through the chimney.
One approach in the prior art for providing a secure closure for the fireplace opening is to employ a panel larger than the fireplace opening with spring members for clamping it to the fireplace as suggested in U.S. Pat. No. 3,789,825 by Reiner. Yet another suggested solution is to suspend plates from pulleys and rope or chain attached sash counterweights as shown in U.S. Pat. Nos. 244,397 by Matthews and 579,987 by Jordan. Multiple pivoted plates have also been suggested as in U.S. Pat. No. 2,743,720 by Dollinger while adaptations of multiple sliding panels for window fire guards have been shown in U.S. Pat. Nos. 381,455 by Bennerscheidt, 866,170 by Watson and 1,234,873 by Clampitt.
Despite the various prior art attempts to resolve the problem, none of the presently known protective devices are satisfactory for enclosing the fireplace opening in a manner which both assures the user that no undetected spark and/or ash escape will occur and further that the residual combustibles will be preserved for later use by smothering of the fire.